top of page
  • Rajani Katta MD

What you’ve heard about Preventive Dermatology on the Internet, and why so much of it is wrong

Updated: Aug 16, 2020

I’ve been writing and speaking on Preventive Dermatology for years because it's such an important topic. The choices you make today regarding skincare, food, and lifestyle can have major impacts on your health, as well the health and appearance of your skin. Unfortunately, I’ve seen a dramatic rise in the number of myths and misconceptions that are spreading on the Internet. Here are just a few that are common and concerning:

spike flowers as an example of nature

Myth #1: Natural is Better

This one always surprises me, because "natural" refers to literally millions of different compounds. Poison ivy is all natural, and there are many, many other plants with similar effects. As I like to put it, there’s "good all natural" and then there's "bad all natural". Coconut oil falls on the good side: it has solid research behind it showing that it has potential to aid in the repair of the skin barrier. Olive oil, on the other hand, has been shown to harm the skin barrier. And citrus oils applied to the skin can actually increase your risk of sunburns.

The bottom line: Learn the facts before just falling for the "natural" label.

This is one of the most common misconceptions among my patients with eczema. That word "hypoallergenic"? It literally has no defined meaning. It is purely a marketing term. The FDA does not define it, so it means whatever the manufacturer wants it to mean.

Jar of hypoallergenic product

Myth #2: Hypoallergenic products are better for those with

sensitive skin.

I’ve seen so-called hypoallergenic products that contain fragrance, formaldehyde, AND methylisothiazolinone. All three of these ingredients are in the top 10 causes of allergic skin reactions in North America.

The bottom line: If you have sensitive skin, ask your dermatologist for products that don't contain highly allergenic ingredients. Here's my list.

Skin, Hair, Nail product safety

Myth #3: Skin, hair, and nail supplements are safe and


No. Just no. There are hundreds of skin, hair, and nail supplements, and some of them can cause serious problems.

When you reach for a supplement, you have no way of knowing whether that supplement is contaminated, safe, or if it even contains what it says on the label. That's because the regulations in the US regarding supplements are almost laughable.

Anybody anywhere can sell a supplement, without providing any proof of quality, safety, or effectiveness before selling it. The FDA can only ask a manufacturer to recall its products after problems have been discovered. This is a REAL concern. Supplements manufactured in the United States have been contaminated with lead, with mercury, with bacteria, and with actual pharmaceutical medications. Others have contained doses of active ingredients that are over 1000 times what's labeled on the product. And that's just the tip of the iceberg.

That’s why I would never consume a supplement that did not undergo third-party independent laboratory testing, indicated with a seal from USP, ConsumerLab, NSF, or Underwriters Laboratories. Personally, I go a lot deeper than that. I don’t recommend any supplements that don’t have significant research demonstrating safety, effectiveness, and the potential for drug interactions.

Store asile of antioxidents

Myth #4: High dose antioxidant supplements can prevent

skin cancer.

This is a very harmful myth. Antioxidants are very important in combating the effects of free radicals and in skin cancer prevention. BUT they have to be at the right dose. That right dose is likely the dose provided by whole foods. Too high a dose, like in some supplements, and you can actually cause more damage. In fact, despite promising lab and animal studies, large human studies of high-dose vitamin C, vitamin E, selenium, and beta-carotene supplements found that they were NOT effective in skin cancer prevention.

Even worse, antioxidants at doses that are too high may increase your risk for cancer of other types. For example, beta-carotene supplements in smokers were actually linked to a higher risk of lung cancer. Even supplements like B9 and B12 have been linked to an increased risk of lung cancer. There is, however, intriguing early research on a different kind of supplement that's being studied for skin cancer prevention. Nicotinamide is NOT a high dose antioxidant. Rather, it appears to work by enhancing the body's own DNA repair mechanisms. In one study, patients with a history of basal cell or squamous cell skin cancer who took nicotinamide for a period of time had lower rates of skin cancers.

The bottom line: Speak with your physician before starting ANY supplement, whether that's a vitamin, a mineral, an herb, or a hormone.

Myth #5:

Diet has no effect on acne/aging skin/eczema/psoriasis.

Myth #6:

Diet is the cause of acne/aging skin/eczema/psoriasis.

Both of these statements are wrong. While it’s highly unlikely that diet is the sole cause of any of these conditions, we have a large body of research demonstrating that dietary choices do have the potential to impact multiple skin conditions. Certain nutrients, foods, and eating patterns have been linked to a worsening of certain skin conditions. And the converse is true as well: certain nutrients, foods, and eating patterns can improve the skin in some cases. As with everything else in medicine, everybody’s different, and recommendations will vary based on your particular medical profile, genetic profile, and skin condition. Unfortunately, I've had patients make some serious dietary changes (with the potential for some serious side effects) based on what someone on the internet wrote worked for them. Six-food elimination diets, for example, have been linked to some severe nutritional deficiencies.

What are some evidence-based strategies? For acne, in addition to standard treatment, diets with a lower glycemic load may be helpful in some (not all) individuals. For eczema, delayed eczematous reactions to certain foods may lead to a worsening of the skin. When it comes to aging skin, diets rich in antioxidant foods have been linked to a younger appearance, while higher blood sugar levels (even in the absence of diabetes) have been linked to a more aged appearance. The bottom line: Chronic skin conditions require an effective treatment plan, whether that's medications, procedures, and/or lifestyle change. For some conditions, dietary change may be an important component of that treatment strategy. And importantly, it's critical to learn the evidence-based research to define the optimal strategy.

Dr. Rajani Katta is the author of Glow: The Dermatologist's Guide to a Whole Foods Younger Skin Diet. To receive future updates on preventive dermatology and the role of diet, sign up here.



bottom of page